With increase in performance of information processing apparatuses, such as a device and a server that are intended for a communication backbone, the data rate at which a signal is transmitted to and received from the respective apparatuses is increasing. The receiving circuit of such transmitting/receiving apparatuses may be a synchronous-type receiving circuit in which sampling is performed in synchronization with a phase of input data or an asynchronous-type receiving circuit in which sampling is performed without synchronizing with a phase of input data. In an asynchronous receiving circuit, interpolation is performed on sampled data by using an interpolation code, thereby generating reception data (see, for example, Japanese Laid-open Patent Publication No. 2007-184847).
A stress test may sometimes be performed on an asynchronous receiving circuit. For example, a test of an operational margin is sometimes performed by reducing the size of an eye pattern (that is, by using a stressed eye). The test of an operational margin using a stressed eye is performed when operations of a transmitting circuit and a receiving circuit are not in synchronization with each other. If the operations of the transmitting circuit and the receiving circuit are in synchronization with each other, the stress test may be performed by controlling an interpolation code (hereinafter, this may be referred to as an interpolation coefficient). When the operations of the transmitting circuit and the receiving circuit are not in synchronization with each other, the stress test may be performed with an interpolation function enabled. As a method for performing the stress test when the operations are not in synchronization with each other, a method has been considered in which points in time at which a data point and a boundary point are sampled are individually controlled. However, this method may make circuitry more complicated or may not be able to provide a correct amplitude.